The Synthesis For A Series Of N-acetylchitooligosaccharides Derivatives

Carbohydrate is one of the three major components for lives. It intervenes and controls many physiological and pathological processes as the information transmission material. Oligosaccharide is an important part of carbohydrate; it is built by 2-10 monosaccharides with glycosidic bond. Due to the differences of monomer molecules, linkage position or connection type, it has different kinds of structure and biological functions. The degradation of oligosaccharide can not control the specific degree of polymerization or certain configurations, so the chemical synthesis is widely used as a controllable method. This paper focuses on the synthesis of N-acetyl lactosamine, N, N-diacetyl Chitobiose and Chitobiose octaacetate.N-Acetyl lactosamine widely exist on the surface of cell membrane antigen oligosaccharide sLea/x, this Lewis antigen is a series of fucose and N-acetyl lactosamine derivatives, which has potential application in cancer diagnosis. In addition, the polysaccharide containing N-acetyl-lactosamine structure unit is galactosidase antigen, and suppress the rejection reaction, therefore the synthesis of N-acetyl-lactosamine is particularly important. In this paper, we use glucosamine and galactose as raw materials, acetyl protection thiogalactopyranoside as the donor, with a catalyst for economic, low toxic, multi-step reaction to synthesis of N-acetyllactosamine with high yield, and a large scale synthesis method was established. At the same time the comparison of thiogalactopyranoside and Schmidt reagent to the same receptor was studied.Chitobiose (GlcNAc-β-1,4-GlcNAc), chitin is high molecular organic compounds built by N-acetyl glucosamine with β-1→4 glycosidic bond condensed. The degradation of chitin and chitosan, obtained chitooligosaccharides has 2-10 N-acetyl glucosamine (or glucosamine) building block. N, N-diacetyl Chitobiose is the key point for the synthesis of chitosan oligosaccharide, the literatures for degradation method are a lot, but the chemical synthesis is merely none. In this paper, we use chemical method with glucosamine hydrochloride as raw materials, to synthesis of N, N-diacetyl Chitobiose and Chitobiose octaacetate, which coupled with N-acetyl glucosamine as receptor and N-Troc protected glucosamine Schmidt reagent as donor. We can obtain these two compounds with high yield, and establish a method for large scale synthesis. At the same time, different receptor and donor in the synthesis was studied.